In a navigation device used in China or United States, a search operation targeted in the whole country is not effective because the navigation device includes a massive and voluminous Point Of Interest (POI) data in a memory. Accordingly, when a user uses the navigation device to search any address or information, the search function for POI information would be performed after she or he inputs or selects a name of province or a name of city. This control method is applicable to most navigation devices which are manufactured or sold in China and United States.
For enhancing efficiency, some of navigation devices may use a global positioning system (GPS) system to recognize current location of a vehicle first, automatically establish the current location based on GPS information to a target region, and provide a search function based on the target region.
That is, a conventional navigation device may acquire GPS information regarding current location of the vehicle from at least one GPS satellite, apply the GPS information on a map data or database (DB) so as to extract information about province or city where the vehicle is currently located, and, responsive to a search term, search POI information in a partial map data or DB associated with the information about province or city when the search term is inputted.
In other words, because of the size of the POI data or DB in the navigation device used in China or United States a search range would be restricted based on the information about province or city so as to maintain search performance because the search performance would be deteriorated when a search function for nationwide is performed.
However, it is inconvenient for a user who would like to search POI information in another region to reset the information about province or city, i.e., restart by inputting a name of another province, or city.